A Peltier element is sometimes used to cool an electronic component such as a CPU. It is disclosed in Jpn. Pat. Appln. KOKAI Publication No. 2000-77585 that a Peltier element absorbs thermal energy from an electronic component to generate electricity and drive a cooling fan by use of the electricity. In another embodiment, it is disclosed that the Peltier element also receives electricity from a power source and absorbs heat. Further, in still another embodiment, it is disclosed that electricity generated by the Peltier element and electricity from the power source are supplied to the cooling fan.
In the technique disclosed in the above document, the Peltier element (thermoelectric element) always performs a heat absorption process or a thermoelectric conversion. Since the Peltier element can perform the heat absorption process and thermoelectric conversion and the heat absorption process and thermoelectric conversion can be selectively used, it is desired to develop a method for usefully utilize the thermoelectric element.
Further, if electricity generated by the Peltier element and electricity from the power source are supplied to the cooling fan, electricity from the power source is supplied to the cooling fan even in a case where the cooling fan can be driven only by electricity generated by the Peltier element. Therefore, the driving time of the apparatus becomes short if it is driven by use of a battery. As a result, it is desired to switch a supply source of driving electricity supplied to the cooling fan between the power source and thermoelectric element.